Pump operating mechanism



Jan. 17, 1939. C, W HALL 2,144,149

PUMP OPERATING MECHANISM Filed oct. 1, `1937 2 sheets-sheet 1 j 45 46 47y. 3 l111i. 2,.

1 WWI/MMM Jan. 17, 1939.

c. w. HALL 2,144,149 PUMP OPERATING MECHANISM Filed Oct. l, 1937 2Sheets-Sheet 2 Patented Jan. 17, 1939 UNITED STATES PATENT OFFICE:

Application October 1,

17 Claims.

This invention relates to pumping equipment and relates moreparticularly to a mechanism for operating a deep well pump.- A generalobject of this invention is to provide -a practical and particularlyeffective pump jack or pumpoperating mechanism.

Deep well pumps such as oil` well pumps are usually operated by awalking beam. The polished rod at the upperend of the pump rod string isconnected with one endof the Walking beam and a crank mechanism isconnected with the other end of the beam to effect its oscillation. Thecrank mechanism usually includes a crank driven by a suitable powermeans and a long link or pitman pivotally connected with the crank andthe beam to transmit movement from the crank to the beam. The crank andpitman drive does not impart a uniform oscillatory movement to the beambut moves the beam in such a manner that the pump rod is operated atdifferent speeds during different phases of its stroke usually movingthe rod at increased speed as it approaches the ends of its stroke. Thisnon-harmonic stroke or non-uniform movement of the pump rod placessevereY strains on the pumping equipment and often causes whipping andfailure of the pump rod;- Where a long stroke pump is' employed it isnecessary to operate the walkingbeam with a long crank and the`condition just mentioned is thus aggravated.

An important object of the present invention is to provide a pump'jackor pump operating mechanism of the walking beam type that corrects orcompensates for irregularities of movement of the beam due to the crankaction, thereby producing a' harmonicV motion or a nearlyV uniformmotion of the pump rod to reduce the strains on the pumping equipmentand permitting an.V increase inthe speed of the pump rod.

Another object of this invention is to provide a pump operatingmechanism of the character mentionedthat may be constructed or regulatedto produce any desired or special movement of l the pump rodwhereoperating conditions warrant or necessitate such movement to'increasethe efficiency of the pump.

Another important object of this invention is to provide a pump jack orWell pump operating mechanism of the walking beam type by means of whichthey pump rod is given a longer stroke and a more rapid movement for agivenmovement of the walking beam whereby less power is required tooperate the pump at a selected orr preferred rate. The mechanism of thepresent invention includes means for increasing or multiplying theextent of movement of the pump rod over that of the walking beam duringeach movement of the beam whereby the beam may be `given a shorter,slower stroke than previously and4 yet effect a reciprocationof thepumprod, atthe desired speed 1937, sensi No. 166,788

and through a stroke of the desired length. This increase-in the rateand length of.movement of the pumprod is accompanied by correction ofthe irregularities of movement of the beam whereby the rod may be givena simple or true harmonic motion.

Another object of this invention is to provide an appliance orattachment for the walking beam of a pump jack that corrects orcompensates for irregularities in the movement of the beamdue to thecrank action whereby the pump rod may be given a simple harmonic motionor any selected special movement and that increases the length and rateof movement of the pump rod.

Another object of this invention is to provide an appliance orattachment of the character mentioned that may be applied to any typicalor standard walking beam with little or no modification.

Another object of this invention is to provide an appliance orattachment of the character mentioned that is simple and inexpensive tomanufacture and install.

A further' object of this invention is to provide an appliance orattachment of the character mentioned that stabilizes the walking beampreventing lateral movement of the beam and the resultant wear of thewalking beam bearing.

The various objects and features of my invention will be fullyunderstood from the following detailed description of typical preferredforms and applications of the invention, throughout which descriptionreference is made to the accompanying drawings, in which:

Figure 1 is a side elevation of the mechanism provided by the presentinvention illustrating the Walking beam and the other parts inintermediate I positions. Fig. 2 is a fragmentary view showing theWalking beam and the rocker at or approaching the upper end of thestroke of the beam. Fig. 3 is a View similar to Fig. 2 showing thewalking beam and the rocker in position at or adjacent the lower end ofthe stroke of the beam. Fig. 4 is an enlarged end elevation of the beamand the rockers being a View taken as indicated by liney 4 4 on Fig. 1.Fig. 5 is a verticaldetailed sectional View takenas indicated'by line 55 on Fig. 4. Fig. 6 is an enlarged vertical detailed sectional viewtaken as indicated by line 6-6 on Fig. 2 and Fig. 7 is a slightlyenlarged fragmentary View similar to Figs. 2 and 3 showing another formof rocker in an intermediate position.

The present invention may be embodied in the form of a complete pumpoperating mechanism or pump jack of the walking beam type or may beembodied in the form of an attachment or appliance for application to apump jack ofthis character. In the following detailed description I willdescribe the invention embodied in the form of an attachmentior a moreor less typical Walking beam type Well pump operating mechanism. It isto be understood that the invention is not to be construed as limited orrestricted to the form or application of the invention about to bedescribed but that it is to be taken as including any features ormodifications that may fall Within the scope of the claims.

The typical walking beam assembly and well equipment illustrated in thedrawings includes a Walking beam I pivotally supported on a Samson postII by a suitable bearing I2. The inner end or 'active end of the walkingbeam I2 is substantially directly above the'tubing head I3 of the welland the polished rod I4 extends upwardly through the head I3 forconnection with the pump operating apparatus. It is to be understoodthat the polished rod I4 is connected with the pump rod of the well pump(not shown) A jack post I5 is located below the outer end of the'beam I0and is provided at its upper end with a bearing I6. The bearing I6rotatably supports a driven shaft I1 and a crank I8 is xed to the shaftI1. A link or pitman I9 operatively connects the outer end of the beamI0 with the crank I8. A pin on the crank I8 pivotally connects the lowerend of the pitman I9 with the crank and a stirrup 2l pivotally connectsthe upper end of the pitman I9 with the rear or outer end of the beamI0. A suitable counterbalance 22 may be carried by the outer end of thewalking beam I0 if desired or necessary.

It is to be understood that the device or attachment provided by thepresent invention is not limited for application to the type of pumpjack just described. The device or attachment of this invention iscapable of use in connection with pumping mechanismsof various types.For example, it may be employed with a pump actuating mechanism having asingle ended oscillating element or beam.

The device or attachment of the present invention includes, generally, ahanger or bearing means V23 on the active or inner end portion of thewalking beam I0, rocker wheels or rockers 24 carried by the bearingmeans 23, a bridle 25 connected with the polished rod I4 and engaged onthe rockers 24, and a cable or line 26 connected with a suitablestationary object and engaging over the rockers 24.

The hanger or bearing means 23 is provided to plvotally mount or supportthe rockers 24 on the Walking beam I0. The means 23 may be variedconsiderably without departing from the broader aspects of theinvention. In the particular case illustrated in the drawings the means23 includes side plates or hanger plates 21 arranged at opposite sides`of the beam I0. The plates 21 are spaced a short distance from the inneror active end of the beam I0 and are substantially vertical to bearagainst the opposite faces of the beam I0. The plates 21 projectupwardly from the upper side of the beam IIJ and have angular partsor'inturned parts 28 that bear downwardly on the upper side of the beam.Tie bolts 29 are arranged through openings in the upper parts 28 of theplates 21 to tie the plates together and clamp them onto the beam I0. Inthe preferred construction the plates 21 project some distancedownwardly beyond the lower side of the beam Ill and have inturnedangular parts 30 in their lower ends. openings in the parts 30 toconnect the lower ends of the plates 21 and to aid in clamping theplates onto the beam I0.

The bearing means 23 further includes a hang- -jecting lower portions ofthe plates 21.

Tie bolts 3l are arranged through er bearing 32 located between theprojecting lower portions of the plates 21 at the under side of the beamIll. The base of the bearing 32 may be secured to the under side of thebeam I0 by screws or bolts 33 and the opposite ends of the bearing aresecured to the plates 21. In practice the bearing 32 may be Welded tothe pro- The bearing 32 has a substantially horizontal opening 34 andthe plates 21 are provided with openings 35 registering with theopposite ends cf the opening 34. A shaft or trunnion 36 extends throughthe openings 34 and 35 and projects laterally or outwardly beyond thetwo spaced plates 21. 'I'he trunnion 36 is preferably forcetted 0rotherwise fixed in the bearing 32. It is to be particularly noted thatthe shaft or trunnion 36 of the bearing means 23 being located at theunder side of the beam I0 has its axis substantially horizontallyaligned with the axis oi' the beam bearing I0 when the walking beam isin a neutral or horizontal position.

'Ihe rockers 24 are important elements of the device serving to move thepump operating bridle 25 in a manner to compensate for irregularmovement of the beam II) and serving to increase the stroke and rate ofthe movement of the bridle. In the preferred construction there are twolike or complementary rockers 24, one rocker being arranged at each sideof the walking beam I0. The rockers 24 are supported by the trunnion 3'6of the bearing means 23 for oscillatory or pivotal movement when thebeam I0 is in operation.

In accordance with the broader aspects of the invention the rockers 24may be varied considerably in construction. In the particular form ofthe invention disclosed in the drawings the rockers 24 each include twospaced hub plates 31 and a channel iron 38 passing between the spacedplates 21. The channel irons 38 extend outwardly from the plates 31 toform two spokes of each rocker 24. Bearings 39 are secured to the hubplates 31 and the channelirons 38. In practice one plate 31 of eachrocker 24 is welded to the closed side of a channel iron 38 and theother plate 31 is welded to the open side of the channel iron and thebearing 39 is welded to the plates 31 and the adjacent side flange ofthe channel iron 38. The bearings 39 are preferably of suil'icientlength to project outwardly beyond the outer plates 31 and the innerends of the bearings may be welded on the flat faces of the inner plates31. The bearings 39 are split or provided with removable caps 40 tofacilitate the assembly of the rockers 24 on the trunnion 36 and may beprovided with suitable bushings or babbitting for cooperating with theprojecting end portions of the trunnion 36.

The rockers 24 further include spokes 4I and 42 radiating or extendingforwardly from their plates 31 and spokes 43 and 44 radiating rearwardlyfrom the plates 31. The spokes 4I, 42, 43 and 44 may be formed of angleiron and their inner endsv may be welded to the plates 31 and thechannel irons 38. A substantially tangential brace 45 extends betweenand connects the outer ends of the spoke 42 and the channel iron 38 ofeach rocker 24. 'Ihe braces 45 may be welded to the spokes 42 and thechannel irons 38. Short spokes 46 may extend outwardly from the hubplates 31 to the braces 45. A cross bar 41 extends between the forwardportions of the braces 45 of the two rockers 24. The bar 41 may bewelded to the upper sides of the braces 45 and is positioned to normallyclear the upper side of Cil the walking beam Ill. VThe bar 41 may engageagainst the upper side of the walking beam III to limit turning of therockers 24 and to limit downward movement of the polished rod I4 when vthe line 25 is being adjusted, replaced or the like. A tie rod 48 passesthrough openings in the lowerv portions of the spokes 44 to connect thetwo wheels 24. The tie rod 4B is suitably connected to the spokes 44 anda spacer 49 may be arranged on the rod between the spokes 44. Theprojecting bearings 39 may be braced by braces 5i! extendinglongitudinally of the spokes 42 and welded on the outer faces of thebearings and spokes.

Each rocker 24 further includes a track or channel 5I for cooperatingwith the bridle 25 and a track or channel 52 for cooperating with theline 26. 'I'he channels 5I of the rockers 24 are elongate curved membersthat are U-shaped or channel-shaped in transverse cross section toreceive the bridle 25. The channels 5I are longitudinally curved and aresecured to the outer ends of the spokes 4i and 42 and the channel irons35. The channels 5I may be secured to these parts of the rockers bywelding. The bridle 25 passes downwardly from the channels 5I to thepolished rod I4, and the channels 5IA are curved in such a manner thatthe portions of the bridle extending downwardly from them remainsubstantially vertical throughout the entire range of movement of thewalking beam I5 and the rockers 24. In practice the major intermediateportions of the channels 5I are substantially concentrically curvedabout the pivotal axis of the rockers 24 and the upper and lower endportions of the channels 5l arerelatively straight and tangent to theintermediate portions. This formation of the channels 5I assures thevertical disposition of the depending portions of the bridle 25 and ofthe polished rod i4 throughout the operation of the mechanism.

In accordance with the invention the channels 5I of the two rockers 24are connected and formed so that the upper portion of the bridle 25 islooped and trained between the two channels. The channels 5I may beintegrally connected by a transverse channel portion 53 that curvesupwardly from the channels 5I and then extends transversely above thebeam lil. rIhe groove in the channel portion 53 faces upwardly so thatthe bridle 25 extending through it is held against displacement and yetis free to shift longitudinally.` This longitudinal freedom of thebridle25 in the channel portion 53 serves to maintain both branches of thebridle 25 under substantially uniform tension and this automaticadjusting of the bridle 25 may aid in preventing lateral shifting of thewalking beam III, Braces 54 may extend from the lower ends of thechannels 5I to the channel irons 38. The braces 54 may be welded to thechannels 5I and the irons 38.

The channels 52 of the rockers 24 are elongate grooved or channel-shapedmembers secured to the outer ends of the spokes 43 and 44 and se-`curedto the rear ends of the channel irons 38.

over the movement of the walking beam I0 and l this ratio may be variedto produce a pump rod stroke of the desired length and speed. Owing tothese factors itis to be understood that the invention is not to beconstrued as limited to any particular curvature or shape of thechannels 52 or to any specific ratio between the ef fective radii of thechannels 5I and 52.

In Figs. l to 5, inclusive, of the drawings the channels 5I and 52 arerelated so that the movement imparted to the polished rod I4 issubstantially proportional to the movement of the walking beam III andthis stroke or movement has a length approximately 1.41 times the lengthof the stroke of the beam II) so that an average stroke of 56 inches ofthe walking beam IIJ will produce an inch stroke of the polished rod I4.In the construction illustrated in the figures just mentioned thechannels 52 are curved substantially concentric with the axis of rockingmovement of the rockers 24 so that the rockers act as a lever having aconstant length.

Fig. 7 of the drawings illustrates a typical variation in the formationof the channels 52. In this figure of the drawings the lower endportions 522L have a radius of curvature greater than that of the upperend portions 52b while the intermediate portions may be curvedsubstantially con- 1 centric with the axis of the rockers 24. Ifchannels 52 of the shape illustrated in Fig. 7 of the drawings areemployed the rockers 24 act as levers having non-uniform effectivelengths and serve to compensate for undesirable irregularities ofmovement of the pump rod that may occur due to the crank action of thewalking beam mechanism. From the above it will be apparent that thespeed of the pump rod stroke may be increased or decreased during anyphase of the stroke by varying the distances of diiferent portions ofthe channels 52 from the axis of the rockers 24. The channels 52 may begiven any desired longitudinal shape to provide for any special orspecific movement of the pump rod.

The bridle 25 may be a single length of cable as illustrated in thedrawings. rIhe bridle 25 has its ends secured to the polished rod I4 bya suit.- able clamp 55 and has two branches extending upwardly from theclamp 55 to engage in the channels 5 I. The upper portion of the bridle25 is looped, as described above, to extend through the connectingchannel portion 53. The bridle 25 is provided to transmit movementbetween the wheels 24 and the polished rod I4, as will be readilyunderstood.

The line 25 is connected with a xed or stationary object and engages thechannels 52 of the rockers 24 to govern the oscillation of the rockersrelative to the beam I0 during operation of the beam. Vihile the line 25may be a rigid rod-like part pivotally connected with a stationaryobject and with the wheels 24 it is preferably a flexible element orcable, as illustrated in the drawings. In the preferred arrangementdisclosed the line 25 has its ends secured to a relatively stationaryobject and is looped to have two branches extend upwardly to engage inthe channels 52. The ends of the line 25 may be secured to the Samsonpost I I. In the construction illustrated in the drawings Y upwardly orupwardly and forwardly so that the line 26 does not become displacedfrom it. 'I'he line 26 being looped in the channel portion 58, as justdescribed, operates to aid in preventing lateral'movement of the walkingbeam III and has its two branches under substantially uniform tension. Y

In the operation of the mechanism the walking beam I0 is operated oroscillated in the usual manner by the crank and pitman drive I 8-I9.Assuming that the beam III is in the position illustrated in Fig. 1 ofthe drawings and that its inner active end is moving upwardly, therockers 24 are caused to rock or turn in a manner to impart increasedupward movement to the polished rod I4. The line 26 is connected withthe rockers 24 by engaging their channels 52 and the line thus serves toprevent bodily upward movement of the rear portions of the rockers withthe beam I0. The result is that the rockers 24 turn on their axisbetween a position such as shown in Fig. 1 to a position such as shownin Fig. 2 during the movement of the walking beam I 0 between itsintermediate position and the upper end of its stroke. As will beapparent from an inspection of Figs. 1 and 2 ofthe drawings this turningof the rockers 24 on their axis adds to or increases the upward motionimparted to the bridle 25 and the polished rod I4. During the downwardstroke of th`e active end of the walking beam Il) the above describedmotion of the rockers 24 is reversed. During the downward movement ofthe walking beam I0 the rockers 24 turn between a position such as shownin Fig. 2 of the drawings to a position such as shown in Fig. 3. Thisturning of the rockers 24 on their axis allows the bridle 25 kto unreelfrom the channels 5I throughout a substantial length of the channels andthereby materially increase the downward movement of the polished rodI4. As the increased movement of the polished rod I4 occurs during theregular stroke of the walking beam I8 it is apparent that the movementof the polished rod I4 is proportionately increased in speed.

As pointed out above, the character, rate and extent of movement of thepolished rod I4 may be controlled to a substantial degree by varying theeffective radius or by varying the configuration of the channels 52.Variation in the radius of the channels 52 variesV the extent ofincrease of movement of the polished rod I4 over that of the active endof the walking beam I0. By varying the shape of the channels 52 theextent and rate of movement of the polished rod I4 may be changed at anyphase of the stroke of the pump to provide for the efficient operationof the pump under practically any circumstances.

Having described only a typical preferred form and application of theinvention, AI do not wish to be limited or restricted to the specificdetails herein set forth, but wish to reserve to myself any variationsor modifications that may appear to those skilled in the art or fallwithin the scope of the following claims:

Having described my invention, I claim:

1. A pump jack for operating a well pump rod comprising an oscillatingelement, a rocker member pivoted on the element, a part connected withthe rocker member and directly connected with a relatively stationaryobject to eiect rocking movement of the member during oscillation of thebeam, and a bridle operating over the rocker member and connected withthe pump rod whereby the rod is operated by the combined movements ofthe beam and member.

2. In combination with an oscillating element and a pump rod, a rockerpivoted on the element,

a port connecting the rocker with a stationary object and havingperipheral contact with the rocker whereby the rocker pivots duringoscillation of the element, and means connecting the rocker and the pumprod whereby the rod is reciprocated by the combined movements of theelement and rocker.

3. In combination with an oscillating element and a pump rod, a rockerpivoted on the element and having a curved peripheral guide, a member fmeans associating the rocker with a relatively f stationary objectwhereby oscillation of the element causes pivoting of the rocker,comprising a connecting member engaging over a peripheral part of therocker and connected with said object and a Iiexible member connectedwith the ..2

rod and engaged by a peripheral portion of the rocker for transmittingmovement between the rocker and the rod.

5. In combination with an oscillating element and a pump rod, a rockerpivoted on the element, c

a line connected with a stationary object and associated with the rockerto engage a peripheral portion thereof for the purpose of controllingrocking of the rocker during oscillation of the beam, and a ilexiblemember connected with the pump rod and associated with the rocker toengage over a peripheral portion thereof and operable to transmitmovement from the rocker to the rod. Y

6. In combination with an oscillating element and a pump rod, a rockerpivoted on the element, a line connected with a stationary object andassociated with the rocker to engage a peripheral portion thereof forthe purpose of controlling rocking of the rocker during oscillation ofthe beam, the contour of said peripheralportion determining the rockingmovement of the rocker, and means for transmitting movement between therocker and the pump rod.

'7. In combination with an oscillating element and a pump rod, a rockerpivoted on the element, a line connected with a stationary object andassociated with the rocker to engage a peripheral portion thereof forthe purpose of controlling rocking of the rocker during oscillation ofthe beam, the contour of said peripheral portion determining the rockingmovement of the rocker, and means for transmitting movement between therocker and the pump rod, said means including a bridle connected withthe rod and rocker and engaging over a peripheral portion of the rockersubstantially diametrically opposite the rst mentioned peripheral.

8. Mechanism for operating a well pump rod comprising, an oscillatablebeam, means for oscillating the beam, a rocker pivotally supported onthe beam, two substantially diametrically opposite peripheral channelson the rocker, a bridle connected with the rocker engaging in onechannel and connected with the pump rod to transmit movement betweentherocker and rod, and a line connected with -the rocker and a relativelystationary object and engaging in the other groove to effect pivoting ofthe rocker during oscillation of the beam.

9. Mechanism for operating a well pump rod comprising, an oscillatablebeam, means for oscillating the beam, a rocker, means pivotallysuplporting the rocker on the under side of the beam, two curvedperipheral channels o'n the rocker, a bridle connected with the rod andthe rocker to transmit movement between them and engaging in one of saidchannels, and a line connected with the rocker and a stationary objectto produce pivoting of the rocker and engaging in the other y of saidchannels, said other of said channels being shaped to cause the desiredpivotal movement of the rocker.

10. In combination with an oscillating beam and a well pump rod, meansfor transmitting movement from the beam to the rod and imparting to therod a stroke longer than the stroke of the beam, said means including, arocker pivotally supported by the beam, the rocker having two peripheralportions, a line connected with the rod and the rocker and cooperatingwith one of said portions, and a line connected with the rocker and astationary object and cooperating with the other of said portions.

11. In' combination with an oscillating beam and a well pump rod, means'for transmitting movement from the beam to the rod and imparting to therod ay stroke longer than the stroke of the beam, said means including,a rocker pivotally supported by the beam, the rocker having twoperipheral portions, a line connected with the rod and the rocker andcooperating with one of said portions, and a line connected with therocker and a stationary object and cooperating with the other of saidportions, the said other peripheral portion. being shaped to vary thevelocity of pivoting movement ci the rocker.

12. In combination with an oscillating beam and a well pump rod, means:for transmitting movement from the beam to the rod and imparting to therod a stroke longer than the stroke of the beam, said means including, arocker pivotally supported by the beam, the rocker having two peripheralportions, a line connected with the rod and the rocker and cooperatingwith one of said portions, and a line connected with the rocker and astationary object and cooperating with the other of said portions, thesaid other peripheral portion having a non-uniform curve to vary thevelocity of pivotal movement of the rocker.

13. In combination with an oscillating beam and a well pump rod, means.for transmitting movement from the beam to the rod and impartf ing tothe rod a stroke longer than the stroke of the beam, said meansincluding, a pair of rockers, bearing means pivotally supporting therockers on the beam to occupy positions at opposite sides oi the beam, abridle connected with the rod and having branches cooperating with outerperipheral portions of the rockers and connected with the rockers totransmit move-- ment between the rockers and the rod, and a looped lineconnected with the rockers and a stationary object and having branchescooperating with the inner peripheral portions of the rockers' to effectand govern pivotal movement of the rockers.

14. In combination with an oscillating beam and a well pump rod, meansfor transmitting movement from the beam to the rod and imparting to therod a stroke longer than the stroke of the beam, said means including, apair of rockers, bearing means pivotally supporting the rockers on theunder side of the beam, means connecting the two rockers forsimultaneous pivoting, a bridle connected with the rod and havingbranches cooperating with outer peripheral portions of the. rockers andconnected with the rockers to transmit movement between, the rockers andthe rod, and a looped line connected with the rockers and a stationaryobject andv having branches cooperating with the inner peripheralportions of the rockers to effect and govern pivotal movement of therockers.

l5. In combination with an Voscillating beam and a well pump rod, meansfor transmitting movement from the beam to the rod and imparting to therod a stroke longer than the stroke of the beam, said means including, apair of rockers, means supporting the rockers at opposite sides of thebeam for pivotal movement about an axis at the under side of the beam,the rockers having inner and outer peripheral channels, a. channel partconnecting the inner channels of the two rockers, a channel partconnecting the outer channels: of the tworockers, a looped bridleconnected with the rod, cooperating with the outer channels of therockers and engaged in the last mentioned channel part to transmitmovement between the rockers and the rod, and a looped line connectedwith a stationary object, cooperating with said inner channels andengaged in the rst mentioned channel part to elTect and govern pivotalmovement of the rockers.

16. In combination with a walking beam, and a pump rod, a rocker elementpivoted on the beam, a looped bridle connected with the rod, spacedchannels on the element in which the bridle engages, a channel partreceiving the loop end portion of the. bridle to associate the bridlewith the element, the cooperation ofl the said part and the bridlepreventing lateral movement of the beam, and means connecting the rockerelement with a relatively stationary object to cause pivoting of therocker during oscillation of the beam.

17. In combination with a walking beam, and a pump rod, la rockerelement pivoted on the beam, a bridle connected with the pump rod andassociated with the rocker element to transmit movement between the rodand element, a looped line connected with a relatively stationaryobject, spaced channels on the element cooperating with the line, and achannel. part on the element shiftably receiving the loop end of theline to connect the line. with the element whereby the element pivotsduring oscillation of the beam, the cooperation of the line. and saidpart preventing lateral movement of the beam.

CHARLES W. HALL.

. y CERTIFICATE OF CORRECTION. Patent No. 2,l`) ll1,lfh.9 January l?,1959.,

CHARLES W. HALL.

l It is hereby certified thaterror appears inthe printed'specificationof the above numbered patent requiring correction as follows: Page )4,second fcolupgl'n, line ll ,yclaim 2, for the word "port" .read part;and that the said :Letters Patent` shouldb'e read with this correctiontherein that the same may conform to the record of the case in thePatent Offieeo signedoan'a sealed this 1mm day of March, Am, 1959.

Henry Van rsdale Sealv) A Acting Commissioner of' Patents.

